[ITK-users] simpleitk Python ExtractImageFilter -- basic usage

[Robert.Atwood at diamond.ac.uk]

I'm sorry if I'm abit thick, but this doesn't work. 
I tried to read documents and old mailing list entries, but I don't find an answer, just in the past someone with a similar problem wound up using CropImageFilter instead. 


Can someone clarify why this doesn't work? I'd specifically LIKE to maintain the origin of the region as the origin of the original image. 


  1 import SimpleITK as sitk
  2
  3 
  4 rawimg = sitk.Image(50,60,70,sitk.sitkFloat32)
  5 newim=sitk.Extract(rawimg,(20,30,40),(0,0,0))



Traceback (most recent call last):
  File "./tryextract.py", line 12, in <module>
    newim=sitk.Extract(rawimg,(20,30,40),(0,0,0))
  File "/home/kny48981/.local/lib/python2.7/site-packages/SimpleITK/SimpleITK.py", line 27140, in Extract
    return _SimpleITK.Extract(*args, **kwargs)
RuntimeError: Exception thrown in SimpleITK Extract: /tmp/SimpleITK-build/ITK-prefix/include/ITK-4.13/itkExtractImageFilter.hxx:99:
itk::ERROR: ExtractImageFilter(0x7f7eb17d8e80): Extraction Region not consistent with output image
[kny48981 at i12-ws011 pycircles]$ python ./tryextract.py  /dls/i12/data/2018/cm19662-3/tmp/bubble/onebub.tif -o /scratch/SSD/robert/onebub
Traceback (most recent call last):
  File "./tryextract.py", line 5, in <module>
    newim=sitk.Extract(rawimg,(20,30,40),(0,0,0))
  File "/home/kny48981/.local/lib/python2.7/site-packages/SimpleITK/SimpleITK.py", line 27140, in Extract
    return _SimpleITK.Extract(*args, **kwargs)
RuntimeError: Exception thrown in SimpleITK Extract: /tmp/SimpleITK-build/ITK-prefix/include/ITK-4.13/itkExtractImageFilter.hxx:99:
itk::ERROR: ExtractImageFilter(0x7f8287a9e020): Extraction Region not consistent with output image


But the output image should be getting created (returned)  by the filter?So how can it not be consistent??? 
 Or what's going on? 
Especially since it worked fine in a previous program with 2d data. 



I tried a bit harder and used the object interface, and compare 2d and 3d, and try to set the collapse strategy.. 

And it works in 2d but not in 3d, I really can't see why. 

  1 import SimpleITK as sitk
  2
  3 rawimg2d = sitk.Image(50,60,sitk.sitkFloat32)
  4 print rawimg2d.GetDimension()
  5 extractor2d=sitk.ExtractImageFilter()
  6 extractor2d.SetSize((20,30))
  7 extractor2d.SetIndex((5,6))
  8 extractor2d.SetDirectionCollapseToStrategy(extractor2d.DIRECTIONCOLLAPSETOIDENTITY)
  9 print "strategy, ",extractor2d.GetDirectionCollapseToStrategy()
 10 newimg2d=extractor2d.Execute(rawimg2d)
 11
 12 print "Finished 2d extractor"
 13
 14 rawimg3d = sitk.Image(50,60,70,sitk.sitkFloat32)
 15 print rawimg3d.GetDimension()
 16 extractor3d=sitk.ExtractImageFilter()
 17 extractor3d.SetSize((20,30,40))
 18 extractor3d.SetIndex((5,6,7))
 19 extractor3d.SetDirectionCollapseToStrategy(extractor3d.DIRECTIONCOLLAPSETOIDENTITY)
 20 print "strategy, ",extractor3d.GetDirectionCollapseToStrategy()
 21 newimg3d=extractor3d.Execute(rawimg3d)
 22 print "Finished 3d extractor"
 23


python ./tryextract.py  /

2
strategy,  1
Finished 2d extractor
3
strategy,  1
Traceback (most recent call last):
  File "./tryextract.py", line 21, in <module>
    newimg3d=extractor3d.Execute(rawimg3d)
  File "/home/kny48981/.local/lib/python2.7/site-packages/SimpleITK/SimpleITK.py", line 27115, in Execute
    return _SimpleITK.ExtractImageFilter_Execute(self, *args)
RuntimeError: Exception thrown in SimpleITK ExtractImageFilter_Execute: /tmp/SimpleITK-build/ITK-prefix/include/ITK-4.13/itkExtractImageFilter.hxx:99:
itk::ERROR: ExtractImageFilter(0x7fbf77727bc0): Extraction Region not consistent with output image



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